Dr. Dan Kelly had been in Sierra Leone only a few days last month when four patients showed up at the Wellbody health clinic he co-founded there, complaining of fevers, diarrhea, weakness and terrible headaches - all symptoms of Ebola.

Wellbody had closed its doors when Ebola cases spiked in Sierra Leone, one of five West African countries at the center of the world's worst outbreak of the deadly disease. But Kelly, a UCSF infectious disease specialist, made an impulsive decision to travel there to help. He reopened his clinic, and trained his staff and others to identify and treat possible Ebola patients and protect themselves. The four sick patients arrived the first day the clinic was up and running again.

Before they could be moved to isolation centers and tested for the virus, however, the patients were gone. The ambulances to move them took too long to arrive, and the patients disappeared - tired of waiting, maybe, or scared.

"They ended up running," Kelly said, even with the training he'd given his staff.

"It feels like the health system is collapsing," said Kelly, who returned to the Bay Area last week. "The solution is to plug all the gaps, but there are so many gaps along the way."

The devastating outbreak of Ebola has sickened more than 4,000 people and killed more than 2,000 so far; recent estimates by the World Health Organization suggest the outbreak could kill more than 20,000 people before it's resolved.

It's been a horrifying spectacle to watch from afar, said Bay Area global health specialists, many of whom have long ties to regions hit hard by the outbreak, or neighboring countries that have suffered less dramatic problems with Ebola.

"I find this very sad to see the country spinning out of control," said Dr. Michele Barry, director of Stanford's Center for Innovation in Global Health, who has worked for years with a teaching hospital in Liberia, where Ebola has hit the population hardest. "I'm so humbled by my Liberian colleagues who are out in the field working there. We're trying to do as much as we can for them here."

Bay Area medical institutions have relationships on the continent that span years or even decades, especially in parts of Africa burdened by the AIDS epidemic. They've built clinics and research facilities and slowly strengthened community-based health care systems. In places like Sierra Leone and Liberia - where the Ebola crisis continues to escalate - those health care systems are still fragile, said Dr. Gavin Yamey, a UCSF global health expert.

Vulnerable countries

"It's perhaps no coincidence that this is out of control in countries that have vulnerabilities, that have not built up their health systems," Yamey said. "They do not have adequate hospitals, clinics, staffing, supply chains of medicines and diagnostic tests. And the global health community has known this for a long time. We need to do better."

Yamey and other global health experts said they hope, at least, that they can leverage the current crisis into more resources to finally develop the health care systems that have been so sorely lacking in West Africa - in countries that are still recovering from years of war and political upheaval.

Even before the outbreak, the health care systems in those countries were insufficient and prone to breakdowns, global health experts said. Those systems have been overrun by Ebola now.

"This outbreak just emphasizes the tenuous nature of many African health systems," said Dr. Warner Greene, director of the Gladstone Institute of Virology and Immunology in San Francisco who has worked extensively in Uganda and other parts of Africa. "This is a tragic but strong example of why we need to be investing in the health of Africa and the health care capacity of Africa in a far more persuasive way."

The outbreak started in March with a handful of cases in Guinea and escalated slowly until this summer, when the case counts suddenly spiked in urban centers and the virus slipped through the porous borders between countries.

But the international health care community has been slow to respond, say infectious disease and global health experts. History had suggested that Ebola outbreaks tended to burn themselves out, which may explain why it took many weeks for the world's responders to identify the situation as the crisis it has become.

Doctors and specialists around the world, including the United States, now are mounting major emergency responses to the outbreak. On Tuesday, the Obama administration said it planned to send up to 3,000 U.S. military personnel to the region to supply medical and logistical support and increase the number of beds needed to isolate and treat patients.

Few countries have sent organized teams of health care providers to the front lines in West Africa, but individuals like Kelly have been there, along with doctors and nurses from private or nonprofit groups.

"There was this complacency, until people started realizing, 'Oh my goodness, it's out of c0ntrol.' And then you're playing catch-up, even now," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases. "You have to mount a much more aggressive effort than we have, and that's what we're starting to do.

"I have always felt that, when it comes to global health, we do have a responsibility as a rich nation to alleviate and help other nations with their struggle," Fauci added. "We don't own this, it's not our problem to solve by ourselves. But we'll be part of an international coalition to address what is a very difficult, tragic global health threat."

But Ebola won't be easy to control, especially now that the virus is raging in well-populated areas. Early on, health care providers could have identified patients and isolated them, then found every person the patient had been in contact with and monitored their health too.

Now, with hundreds of new cases every week in some countries, the task seems impossible. It would threaten the structure of even a well-developed health system like in the United States - it's burying the health infrastructure in West Africa.

That weak infrastructure is also what's keeping so many doctors, nurses and other health care providers who might otherwise volunteer from traveling overseas to help.

Recruiting campaigns

In the past week or two, several international aid organizations have begun major campaigns to recruit doctors and other health care providers to the West African nations. Partners in Health, a Boston nonprofit that works in poor communities around the world and has helped support Kelly's clinic in Sierra Leone, announced last week that it is looking for volunteers.

"I know there are more Dan Kellys out there. We need all hands on deck," said Dr. Paul Farmer, Partners in Health's co-founder and chairman of the global health department at Harvard Medical School. Farmer will be traveling to Liberia next month to start work building a new treatment center.

But traveling to the affected areas has become a major hurdle now - it took Kelly almost three days and multiple canceled and altered flights.

Another obstacle may be the concern heath care providers have for their safety - that they won't have access to proper equipment, or that if they do get sick, they won't get proper care. There's no guarantee that American workers who become infected with Ebola will be evacuated back to the United States, although that's been the case so far.

Kelly had been in Sierra Leone for two weeks in June, mostly to do administrative work at the clinic. At the time, the Ebola outbreak was concerning but not a crisis that Kelly or his staff was immediately worried about.

But the situation quickly worsened. On Aug. 13, a doctor who was a close friend and mentor of Kelly's died after contracting Ebola; Kelly reserved a plane ticket that night.

"It was very anxiety-provoking getting there. And everyone was telling me it was a bad idea," Kelly said. "I was thinking, 'If I get Ebola I'm screwed.' But I just felt 100 percent compelled to go. It felt like the right thing to do."

Kelly contacted friends and colleagues in Sierra Leone to offer his services, and was told that two hospitals had temporarily shut down because the workers there weren't trained to identify cases and prevent the spread of infection. They asked Kelly to do that training.

He said he trained about 1,000 people in all, in daily classes that were always packed. He didn't treat any Ebola patients - before this trip, he'd never even seen a case of the disease - but he met with several of them.

Many patients, he said, have died in isolation centers before they could get treated, sometimes before lab tests could confirm they had the virus. In an essay that was published in the journal Nature last week, Kelly wrote that building diagnostic centers in addition to clinics to isolate and treat patients is essential to stopping the outbreak.

Kelly eventually tried to track down the four patients who had stopped by his clinic with symptoms of Ebola. One of them, a man he knew well, turned up in a government hospital in a general ward.

Patient not in isolation

"I was standing there talking to him and the medical director of the hospital came by and said he needed to talk to me. And he said, 'This man just tested positive for Ebola,' " Kelly said. "It was a shock. He was in the general ward, not even isolated."

When Kelly returned to San Francisco last week, he almost immediately requested a leave of absence from UCSF. He has more work to do in Sierra Leone, he said. He's planning to return in a month, and stay through the end of the year.

"I felt like I won some small battles while I was there," Kelly said. "But in general, we're losing this war. The situation isn't getting better. I need to be there. I need to be on the ground."

Find out more

For more information about Wellbody Alliance, Dr. Dan Kelly's nonprofit working in Sierra Leone: www.wellbodyalliance.org.

About the current Ebola outbreak

-- 4,366 confirmed cases and 2,218 deaths, making it the deadliest Ebola outbreak recorded. The survival rate is just under 50 percent.

-- Five countries affected: Guinea, where it began in March; Liberia; Nigeria; Senegal; and Sierra Leone. Three of those countries - Guinea, Liberia and Sierra Leone - have widespread disease.

-- Liberia has been hardest hit, with more than 1,000 deaths and increasing case counts every week.